Drill bit guide



i pril 6, 1937. R. MILLER DRILL BIT GUIDE Filed June 22, 1956 A, //f//ssss L "ZN INVENTOR RUSSEL MILLER BY Wf/f rroRNL-Y Patented Apr. 6, 1937 UNITE-D STATES PATENT loFFicla 5 Claims.

The object of the invention is to provide means 'i'or counteracting the tendency of a drill bit to deviate from a vertical line when entering a hard inclined strata of rock and to steady the drill bit and the rod adjacent thereto.

-The invention consists essentially of a device adapted to be mounted upon a drill rod adjacent to the bit, which device is provided with a plurality of rocking cams capable of being brought into action in response to side thrust upon the drill bit, which cams set up a reaction to said thrust, as will be more fully described in the following specification and shown in the accompanying drawing, in which:-

Fig. 1 is a general view of the invention showing the device mounted upon a drill rod and the drill; bit about to enter an inclined strata of roc Fig. 2 is a transverse section of the guide tak`en on the line 2-2 of Figure l.

Fig. 3 is a transverse sectional view as in Figure 2 but showing the action of thecams.

In the drawing like characters of reference indicate corresponding parts in each figure.

'I'he numeral I indicates generallya well bore in which a drill -rod 2, fitted with a fish tail or other suitable rotary bit 3 isrotatable. The numeral 4 indicates an inclined hard formation about to be encountered by the bit 3. Mounted upon the drill rod, in close proximity to the drill bit 3, is the guide which is generally indicated by the numeral 5.

The guide 5 consists of a sleeve Ii which is rotatable upon the drill rod 2 and is.. provided on its outer periphery with a plurality of ribs 1 which define between each pair of them a groove 8. Rockingly mounted upon their apices'9 in each of these grooves, is a triangular shaped cam I0. The cams I0 each have sides II and I2 and a peripheral face I3, the'side I2 being slightly longer than the side I I. s

Surrounding the cams I0, but normally out of contact therewith, is a. cylindrical casing Il hav.

ing the same external diameter as the' drill bit and the well bore adjacent' thereto; Between each pair of 'cams I0 is a cushion I5 which is v preferably made of rubber,- with'a vertical opening I6 extending therethrough which serves as a' passage to permit the ow of water and mud from the bottom of the well. These cushions serve to hold the cams I0 in their normal position when the guide is not operating td straighten the bOre.

(Cl. Z55-"28) and to urge the cams back to normal position after they have been moved about their apices.

In use, the guide will turn around in the well bore so long as the bit is cutting a substantially straight hole, but when the bit encounters an inclined strata which throws said bit to one side, which would be to the left with a formation as shown in Figure 1, the cushions I5 in the left side of the casing I4 would be brought into compression and the caml IDA, see Figure 2, would be thrust over until its face I3 contacted with the inner periphery of the casing I4, which would have been thrust into firm and non-rotative contact with the left side of the Well bore.

The sleeve 6, due to side pressure from the drill rod 2 and resistance set up thereby, would turn with the rod 2 and upset the position of the cam IIIA, causing it to rock in an anti-clockwise direction and develop a thrust along its side I2 to urge the sleeve 6, the drill rod 2 and the drill bit 3 in a direction substantially opposite to that of the original thrust on encountering the rock strata 4. When the resistance to the rocking of the cam IDA becomes greater than the resistance to turning of the drill rod 2, which has been set up mostly by side pressure, the drill rod will slip momentarily, allowing the rubber cushion behind the cam IIIA to resume its normal form and let said cam return to normal position, at the same time allowing the casing I4 to turn for a moment or' until the side thrust on the drill, due to rock formation again thrusts the casing into firm contact with the side of the well bore, when the function above described will be repeated, except that one of the following cams will come into operation to produce the counter thrust through the drill rod to the bit.

vWhat I claim as my invention is:

l. A guide for rotary drill bits comprising a sleeve adapted to be rotatably mounted upon a drill rod adjacent the drill bit, a casing surrounding the sleeve and adapted to substantially contact the sides of the hole drilled by the bit, resilient material normally supporting the casing concentrically to the sleeve, and. means other than the supporting means operable in response to side thrust upon the drill bit for imparting a thrust to the sleeve counter to the thrust upon the drill bit.

2. A guide for rotary drill bits comprising a. sleeve adapted to be rotatably .mounted'uponn a. drill rod adjacent the drill bit, a casing surrounding the sleeve and adapted to substantiallycontact the sides of the hole drilled by the bit, resilient material normally supporting the casing coneentrically to the sleeve, a plurality of cams interposed between the sleeve and the casing, and means as a predetermined pressure is exerted between the sleeve and one side of the casing when the sleeve is rotating for rocking a cam close to the line of thrust and for exerting a thrust upon said sleeve counter to the direction of thrust upon the sleeve.

3. A guide for rotary drill bits comprising a sleeve adapted to be rotatably mounted upon a drill rod adjacent the drill bit, a casing normally concentrically mounted about the sleeve, a plurality of cams mounted radially of the sleeve and normally out of contact with the casing, means for holding the cams in normally inoperative position, said cams being adapted to be progressively brought into contact with the casing and rocked upon their axis on rotation of the sleeve when a predetermined side thrust is imparted to the sleeve whereby a thrust is imparted to the sleeve in a substantially opposite direction to the side thrust upon the sleeve.

4. A guide for rotary sleeve. adapted to be rotatably mounted upon a drill rod adjacent the drill bit, a, casing normally drill bits comprising a .drill rod adjacent the dr'll bit, a casing normally concentrically mounted about the sleeve and adapted to substantially t the bore of the well being drilled, a plurality of cams disposed radially of the sleeve, cushioning members supporting the casing from the sleeve and for resiliently holding the cams in normally inoperative position, one of said cams being adapted in response to side thrust upon the sleeve to rock and exert a thrust between the wall of the casing and the sleeve counter to the side thrust.

' RUSSEL MILLER. 

